Adjustable diffuser blades



Oct.` 3l, 1967 J, BERAN ET AL 3,349,997

ADJUSTABLE DIFFUSER BLADES Filed May 4, 1966 United States Patent() 3,349,997 ADIUSTABLE DIFFUSER BLADES Jaromr Beran, Chabry u Prahy, and Du`s'an Misrek, and Miroslav Futera, Prague, Czechoslovakia, assignors to Ckd Praha, oborovy'I podnik, Prague, ICzechoslovakia Filed May 4, 1966, Ser. No. 547,579 Claims priority, application Czechoslovakia, May 5, 1965, 2,936/65 2 Claims. (Cl. 230-114) This invention relates to a device for adjusting diffuser blades particularly for use in turbo-compressors equipped with automatic control for adjusting the diffuser blades.

Conventional devices of this kind substantially consist in two coaxial rings, one of which being stationary and the other being rotatably mounted thereon. The stationary ring carries pivot pins of the diffuser blades, equidistantly spaced in circumferential relationship to each other. To provide a control for simultaneous adjustment of the diffuser blades, their pivot pins have arms, which are interconnected by pull rods and pins, with the rotatable ring.

Adjustable diffuser blades having such control device ,have been used heretofore, but were not successful, be-

cause a considerable effort was necessary to rotate the dilfuser blades for adjustment together with the rotatable ring. Moreover, such device is diicult to assemble due to its intricate construction and its machining, requiring high precision machining methods, is costly.

It is an object of the invention to provide for an easy rotation of the diffuser blades to adjust them, by mount ing the rotatable pins of the diffuser blades on a rotatable ring which is coaxial with a stationary ring, with a radial arm articulated with its free end to the stationary ring.

The foregoing and additional objects of this invention will be readily apparent from the following detailed description of a preferred embodiment thereof when considered with the accompanying drawing in which:

FIGURE 1 is a partial transverse section and an elevational view of the diffuser unit of a radial turbo-compressor with a blade adjusting device;

FIGURE 2 is a section taken in the direction of line II-II of FIGURE l;

FIGURE 3 is a section taken in the direction of line III-III of FIGURE 1.

Referring now to the drawing in detail, there is seen in FIGURE 1 a shaft 1 of a rotor (not shown) of a radial turbo-compressor, about which circumferentially and equally spaced diffuser blades 2 are mounted on a rotatable ring 4. Each of the diffuser blades 2 is attached by a pin 3 to this rotatable ring 4 to rotate thereon. The rotatable ring 4 is mounted on the outer circumference of a stationary ring 5 with the aid of anti-friction means, e.g. balls 6, inserted into appropriate ring grooves 7, provided in adjacent walls both of adjustable ring 4 and stationary ring 5, as illustrated in FIGURES 2 and 3. Each of the pins 3 of the diffuser blades 2 is provided with a radially extending arm 9 having the shape of a cylindrical bolt, whose other end is, in turn, articulated to the stationary ring 5. The articulation is such that the radial arm 9 is adapted to pass, in sliding engagement, through a transverse bore 10, provided in a guide pin 11. All of the guide pins 11 are disposed in the stationary ring 5 to rotate therein. There is provided on the outer circumference of the stationary ring 5 an annular recess 12, which is to receive radial arms 9 of the diffuser blade pins 3, as well as their guide pins 11, freely inserted therein, as can best be seen in FIGURES 2 and 3. Moreover, spacer springs 8, e.g. U-shaped ilat springs, are disposed in recess 12 which are adapted to keep the balls 6 in spaced relation to one another. The bent portion of spacer spring 8 is adapted to surround both the guide pin 11 and the free end of radial arm 9.

To the rotatable ring 4 a pull rod of circular section, actuated e.g. from a servomotor (not shown), is connected by a joint 13. To facilitate assembling, stationary ring 5 is composed of two portions which are bolted together, the annular recess 12 being provided therebetween.

As the turbo-compressor is being controlled, the movement from the non-illustrated servomotor is transmitted through intermediation of pull rod 14 on to the rotatable ring 4, on which all of the pins 3 of diffuser blades 2 are mounted. With the rotatable ring 4 moving in respect to the stationary ring 5, radial arms 9, too, perform angular movement and operate, at the same time, pins 3 to rotate together with the diffuser blades 2. As the diifuser blades 2 are rotated the flow area therebetween is variable.

Thus an improved adjustable blade assembly is provided, in which also forces or gas pressure acting on the rotatable ring are utilized in order to reduce the effort of control and, consequently, to reduce the size of the servomotor and of the equipment proper. Moreover, manufacturing and assembling of the individual component parts is less expensive and their sealing more reliable. This is of particular importance Where gases are being compressed which tend to dissolve or extract mineral lubricants as used for lubrication of the equipment and thus increase passive resistances of the adjusting mechanism. The complete equipment constitutes a self-contained unit, which can be assembled beyond the turbocompressor itself.

Obviously, various changes and modifications may be made without departing from the invention. It will be therefore understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a device for adjusting diffuser blades of a turbocompressor in combination:

(a) a stationary ring and a rotatable ring coaxially mounted thereon;

(1) between said stationary n'ng and said rotatable ring are provided antifriction means,

running in circular grooves in both of said rings,

(2) -said antifr'iction means being kept in spaced relationship by Hat spring means,

(3) said flat spring means being U-shaped;

(b) a plurality of pin means circumferentially equally spaced and mounted on said rotatable ring to rotate thereon,

(c) a plurality of blade means each of them mounted on one of said pin means to rotate therewith,

(d) bolt-like members one radially extending from each of said pin means and with its other end connected with said stationary ring,

(l) said radially extending members each being in sliding engagement with a guide pin which is disposed in said stationary ring and is adapted to rotate therein,

(2) said guide pin having a transverse bore and said other end of said radial member slidingly extends therethrough,

(3) said guide .pin together with said other end of radial member surrounded by a bent of said U-shaped spring means;

(e) control means operatively associated with said rotatable ring and adapted to rotate said rotatable References Cited ring together with said blades to adjust ow passage UNITED STATES PATENTS area therebetween. 2. In a device as set forth in clairn 1, wherein on the 1136877 4/1915 Homersham 23o-114 2,645,410 7/1953 Bauger et al 230-114 outer circumference of said stationary ring an annular 5 recess is provided, into which said radial members of said pin means and said at springs means are loosely inserted. LAURENCE V' EFNER Primary Examiner' 

1. IN A DEVICE FOR ADJUSTING DIFFUSER BLADES OF A TURBOCOMPRESSOR IN COMBINATION: (A) A STATIONARY RING AND A ROTATABLE RING COAXIALLY MOUNTED THEREON; (1) BETWEEN SAID STATIONARY RING AND SAID ROTATABLE RING ARE PROVIDED ANTIFRICTION MEANS, RUNNING IN CIRCULAR GROOVES IN BOTH OF SAID RINGS, (2) SAID ANTIFRICTION MEANS BEING KEPT IN SPACED RELATIONSHIP BY FLAT SPRING MEANS, (3) SAID FLAT SPRING MEANS BEING U-SHAPED; (B) A PLURALITY OF PIN MEANS CIRCUMFERENTIALLY EQUALLY SPACED AND MOUNTED ON SAID ROTATABLE RING TO ROTATE THEREON, (C) A PLURALITY OF BLADE MEANS EACH OF THEM MOUNTED ON ONE OF SAID PIN MEANS TO ROTATE THEREWITH, 